4-20ma to 0-10 volt conversion

Can you settle for 2 to 10 Volts?

you just use a voltage network to feed the transmitter from converter. with this network, you can use an Op-amp with dual rail supply or some negative offset to give you 0 volts at 4 ma's something like a 24 DC supply using a 100 ohm Resistor to supply the transmitter. The op-amp simply uses both inputs to monitor the offset of the voltage on this resistor, which will translate to a voltage output..

An operational amplifier is versatile and capable of performing the conversion. Assuming you have a single 15V supply, here's an LM324- based circuit that will do the job fairly well (view in fixed font or M $ Notepad):

| VCC | + | | | .-. | 12K| | | | | | '-' VCC | | + | .-. |\\| Set For Vo = 0V | 1K| |-o--------.(1V) | '-' .---|-/ | | | | | |/| | | ___ | === | GND | | .---|___|---. | GND | | | | 25.5K | | '--------' | | | | | ___ | |\\ | | + |\\ '---|___|-o---|-\\ | | o----o-------|+\\ ___ 10.2K | >----o---o Vo |I(in) | | >-o--|___|-o-------------|+/ | .-. .---|-/ | 10.2K | |/ | 249| | | |/ | .-. | | | | | 25.5K| | | '-' | | | | | - | '--------' '-' | o----o | | | === | === GND | GND (created by AACircuit v1.28.6 beta 04/19/05

The 249 ohm terminating resistor for your current loop will produce a

These are standard 1% resistor values. If you need/want 5% components, try using 30K and 12K in place of the 10.2K and 25.5K. If you need more accuracy, you might want to replace the LM324 with a lower drift single supply quad op amp, and use a voltage reference instead of your power supply to create the subtracting 1V.

Good luck Chris